A power transformer typically includes a housing containing oil that is used to cool the coils of the power transformer. Over time, the oil deteriorates and becomes less efficient in operating as a cooling agent. Consequently, the oil contained inside the power transformer is periodically replaced with fresh oil. The oil replacement procedure is generally carried out by injecting fresh oil into a first valve-controlled port of the housing while draining out the old oil via a second valve-controlled port of the housing. Using such a draining procedure ensures that the fresh oil flushes out the old oil. However, this operation requires that various fixtures (piping, insulation, gaskets, tanks etc.) be provided on each of the two valve-controlled ports and, thus, reserved for performing oil replacement procedures.